The present invention relates to a termination method and apparatus for cables and conduits. The invention is especially concerned with such termination methods for use with conduit, braided bundle, or cable (unless specified, referred to collectively herein as "conduit"). The conduit is used, inter alia: (1) to provide electromagnetic shielding for any number of electrical circuits, (2) to provide structural protection to the wires, and (3) in some cases, to provide environmental protection to the wires.
The termination end fitting connects the conduit to end unit hardware. Prior art end fittings typically consist of a ferrule that can be integrally or otherwise attached to any number of different types of hardware configurations depending on the application. The termination is achieved by inserting the ferrule portion of the end fitting into the end of the conduit then securing, by a number of different methods, a clamp or collar around the outside of the conduit to secure the conduit to the end fitting.
The prior art termination methods ordinarily secure the conduit between the collar and end fitting by soldering, brazing, crimping, or swaging. However, the termination methods of the prior art are quite labor intensive, and may have other disadvantages as well.
For example, soldering involves many steps that take up to 20 minutes or more to complete per end fitting. If a type of conduit with a braided sheath is terminated by the soldering method, the braided sheath must be prepared to prevent any fraying. Then the collar and end fitting are soldered to the conduit. Preparing the final assembly typically involves tamping, grinding, reaming, and finally cleaning. This method often requires special chemicals and a heat source and is therefore very difficult to assemble in the field.
Crimping, in which a collar is physically compressed around the conduit, requires special tooling to support the inner diameter of the ferrule to prevent it from collapsing. This termination method may also take up to 20 minutes or more to complete per end fitting. The other methods of termination are similarly time-consuming and complex.
Some termination methods, such as soldering create internal sharp edges that can damage electrical conductors. Methods which produce external sharp edges, such as clamps, are also disfavored by end users due to their potential to cause damage, either to the conduit itself or to the surrounding environment. It is also preferable for the termination method to provide 360.degree. of mechanical and electrical contact in order to retard electromagnetic interference, and to enhance the structural integrity of the connection.